What's the rationale behind her blocking me on WhatsApp?

My crush's girlfriend will block me on WhatsApp every now and then for no reason. I don't even contact her at all, and we know each other on WhatsApp only because of a group chat for our part time job. How I know she blocked me is her profile pic will disappear for a while them reappear when it's near the day of our part time duty where we have to report in the group chat.

So what could be her reason for blocking me like that? It's so pointless!

What's the rationale behind her blocking me on WhatsApp?
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